1. Field of the Invention
The present invention relates to a portable reciprocating saw having a saw blade which performs an orbital motion in which a first path during forward travel is different from a second path during return travel.
2. Description of the Prior Art
In a conventional Portable reciprocating saw of this type, rotation from the drive motor is converted into a reciprocating motion, which is transmitted to a slider carrying a saw blade. Thus, the slider is reciprocatingly moved to perform a cutting operation. Furthermore, in order to improve the efficiency of operation, the reciprocating motion of the slider is combined with a pivotal motion so as to impart an orbital motion to the slider or the saw blade.
Various mechanisms and arrangements have been devised heretofore to impart such an orbital motion in a reciprocating saw. For example, Japanese Laid-Open Utility Model Publication Nos. 57-183105 and 57-185502 disclose such an arrangement in which means for converting rotation from a drive motor into a reciprocating motion to be transmitted to a slider includes cam means so as to impart to the slider a pivotal motion in association with the reciprocating motion. U.S. Pat. No. 4,385,443 discloses another arrangement in which a bevel gear serving as motion converting means has its axis inclined to a plane transverse to the axis of reciprocation of the slider so as to impart to the slider a pivotal motion in association with the reciprocating motion
However, the former arrangement of the above mentioned prior art is disadvantageous in that provision of the cam means inevitably causes the structure to be complicated In the latter arrangement, the noted cam means is omitted by inclining the bevel gear However, as the axis of the bevel gear is inclined only to a plane transverse to the axis of reciprocation of the slider, the arrangement cannot impart the above mentioned orbital motion but an arcuate motion having a forward travel and a return travel in a common path. Therefore, suitable connecting means different from the above mentioned cam means must be provided at the connection between the bevel gear and the slider. This disadvantageously causes the arrangement to be complicated.